Hybrid Engine Systems and Sustainability

Mmmhh, then how about hanging the cable above the boat, like a tram or trolley-car?

 

Nothing to suspend the wire above the ferry.
Those street car cables are held up every 50 ft with a pole.

 

http://en.wikipedia.org/wiki/canby_ferry

 

Hmmm, who knew ! haha.

 

"The real problem is folks want to compare green systems, with small block Chevy powered craft, which is just way outside the reasonable possibilities."

I am no expert but I believe this is the real problem. What needs to be compared are the merits of alternative systems relative to the type of boat and how it will be used. If we are talking about a small sailing auxiliary cruiser that uses its engine for propulsion on average about two hours a day, but requires a powered anchor windlass, fridge ,freezer , autopilot ,water maker, electronics ,and an entertainment center, then I think the solar electric sail hybrid is worth looking into.

Some numbers that may or may not be entirely accurate or germane.

4 stroke generator
run time full tank 4 hrs
dry weight manual start 50lbs

2000wats 4hrs a day 8 kwh
30 gals per month
weight 180lbs

8hp manual start 4 stroke outboard 92 lbs

1 gal per hour
60 gal per month
weight 360lbs

2 12V 300AH Lithium Ion Battery
Amp Hours: 300
20A @ 900 Minutes
Life in Cycles: 3000-5000
weight 186 lbs

total system weight no fuel 328 lbs half fuel 598lbs full fuel 868lbs



solar panels 3000wats 120 lbs
5hrs 8 to 12kwh a day
8hp electric outboard 40 lbs

4 12V 300AH Lithium Ion Battery
Amp Hours: 300
20A @ 900 Minutes
Life in Cycles: 3000-5000
weight 372lbs

total system weight 532lbs

 

A sport fisherman who needs a powerful diesel engine to reach the fishing grounds...then a silent electric engine to troll or fish ...would be a prime candidate for diesel electric.

 

Electric motors could probably be used right NOW for low speed use.
Houseboats, trawlers.
I think we're decades away from talking about an electric speed boat that could run for more than a few minutes.

 

I think the term 'hybrid' is co-opted by marketing to take advantage of the terms success in cars.

As stated before, sailboats of the past are 'green'er than anything marketed today. But there is plenty of technology available to make the sailing condominiums of today have a lower environmental impact or more universally valuable by reducing dependency on shore supplies.

Prop power and torque requirements don't match up with IC engine output at all but they are an easy match to electric motors. This alone justifies electric motor/generator systems. In a luxury aux sailboat, the electrical power demands are so high that it is cheaper to just increase the electrical system size and swap out the second diesel for electric propulsion. In low power conditions (motor sailing) electric rules. It could add thrust only as needed, without noise or vibration, or even take thrust and act like a water generator. What I think is missing today is a diesel generator with an auto style hybrid transmission so you could run the prop from either the diesel or electric motor/generator.

 

That is a big blanket statement. It has been discussed many times here that the added cost and complexity AND efficiency losses are not worth the hassle. If such optimizing (torque curve of the engine) is wanted variable pitch propeller is a good solution. Not cheap but doesn't need as complex system as using diesel electric just to serve as a transmission.

Diesel electrics are used in certain special cases where other considerations justify them. For a typical pleasure or work boat they are a novelty.

 

Looking at diesel a fuel map the easy way to get efficiency is a cruse prop.

This is an over sized prop that simply loads the engine far better at lower RPM.

The danger of course is the engine could be overloaded and harmed by an attempt to run to the OLD mfg rated RPM.

An EGT gauge and a red line on the tach that is observed would solve the problem,

BUT few are willing to oversize a prop enough to really get loaded to the real efficiency the engine can deliver.

"what about running to beat a hurricane or steaming into a 50K breeze with 20 ft waves?"

A CPP will help a bit but it takes diameter not just a pitch change to absorb HP.

A second solution could be a ZF 2v speed transmission.One gear would allow the std engine mfg specks for full throttle.

The shaft speed could be raised as the boat slows to Long Range Cruise then the pitch optimized with the CPP and EGT gauge.

No battery for thousands , charge controllers , no second motor, no Boeing fires,, yet the engine is optimized for cruise with decades reliable OTS mechanical parts.

ZF 2 speed isn't cheap , but the boat will have to have a tranny anyway.

And cruising at low engine RPM is usually smoother and quieter.

Easy to enjoy as you save fuel, with no pioneer $$$$$$ risk.

 

> The danger of course is the engine could be overloaded and harmed by an attempt to run to the OLD mfg rated RPM.

In this case, this is pretty much a myth*. The oversized prop would not allow the engine to reach the rated RPM or max HP output. This is efficient and does NOT harm an engine.

* - some things to avoid with any prop: running rich, extended very low outputs (like idle), max load (at any rpm but especially below peak torque rpm), max rated output.

 

Yet another variable in the mix: the Carbon Index imperative. Here's an example
http://gcaptain.com/hybrid-eco-tug-...ed&utm_campaign=Feed: Gcaptain (gCaptain.com)

 

There is a very good article in the current issue of Professional Boatbuilder magazine, issue no. 142, April/May 2013, by Nigel Calder, the fourth in a series in which he has documented his on-board testing of various hybrid propultion systems. The other articles in the series are:

#107--June/July 2007
#108--Aug/Sept 2007
#127--Oct/Nov 2010

He has been searching for answers regarding efficiency by conducting full-scale tests on his Malo 46 sailboat. He has been getting funding and in-kind support from engine, electric motor, battery, and propeller manufacturers. In the current metric, he has been plotting specific fuel consumption (grams/kWHr) and absolute fuel consumption vs. boat speed.

He first makes a distinction between serial and parallel hybrid systems. In a serial system, the engine is not connected to the propeller shaft. The engine drives a generator which drives an electric motor attached to the propeller shaft. The engine can also charge batteries. In a parallel system, both the engine and electric motor are connected to the propeller shaft. The engine can also drive a generator that can charge batteries.

All parts of the system--engine, motor, batteries, and propeller--have losses which degrade efficiency, and Nigel discusses these in detail and how, when looking at fuel consumption vs. boat speed, there is an ultimate overall "crossover point" which defines when propulsion by the electric part of the system is more efficient vs. when propulsion by the engine part of the system is more efficient. In one chart, he shows various types of crossover points with 10 different propellers. The crossover point with the worst propeller (he does not identify brands in this article) the crossover point is at 4.3 knots boat speed, whereas with the best propeller it is at 6.3 knots--a 46% difference! That is, below these crossover speeds on this particular boat and set-up, running under electric power is more efficient in terms of fuel consumption, and above these speeds the engine is more efficient.

To quote some interesting conclusions from the article:

"Although in percentage terms, the increases in above-the-crossover-speed fuel sonsumption of the hybrid systems are nowhere near as great as the gains below the crossover speed, in absolute terms (litres per hour), the hybrid losses rapidly dwarf any gains below the crossover speed. This is the Achilles heel of a serial system: if vessel operation requires any sustained operation above the corssover speed (typically 'cruising' speeds will be above that threshold), the losses will rapidly overwhelm any gains below the crossover speed, for a net loss of efficiency. The same problem is not true of parallel systems, because when the vessel is operating above the crossover speed, it will be under engine power."

But Nigel goes on to say:

"Parallel hybrid systems must pay the battery-loss penalty, which lowers the crossover speed, but so long as electric operation is kept below the crossover speed, the parallel system will always show a net gain in efficiency. This may be quite substantial in percentage terms, although, as we have seen, it will typically be modest in absolute terms."

Nigel goes onto discuss other ancilliary issues of hybrid systems, such as the effects of all the other house consumers using up some of the electricity, as well as the lifestyle issues such as very quiet running. It is hard to put a price on that particularly.

I have heard Nigel discuss his research at IBEX the last few years, and it has been very enlightening, and this article sums up all that he has found.

Eric

 

Slightly off topic, but I wonder if anyones ever taken a sailboat, swapped the sails for wind generators, installed an electric motor, and batteries ?
I'm not experienced with sail boats, but I think I understand the basics.
Use a bunch of batteries as keel weight, swap all sails for wind towers, and install an electrical drive system to propel the boat.

It could be "wind-diesel-battery-electric".
Since the wind generators aim themselves into the wind, all you'd have to do is drive the thing, and try to not aim straight into the wind.

 

Maybe even a 10 kw bugger like this would move a few boats:

http://www.ebay.com/itm/New-2013-Mo...339?pt=LH_DefaultDomain_0&hash=item27d0527cab

UUUggghhh, weight 2600 lbs !
I suppose though, the mast wouldn't need to go as high as normal, just to the pod.
Maybe there are lighter ones.
I don't know lol.
I looks like a generator that size probably is about 25+ feet in diameter, so the tower would need to be at least 21 ft high to give 8 ft from deck to blade tip.